Distributing means



Aug. 9, 1938. E. R. TRoxELL, JR 2,126,230

' DISTRIBUTING MEANS Filed A ug. 18. 1934 Z ll 'whim i UI Patented Aug. 9, 1938l PATENT OFFICE` DISTRIBUTING MEANS Edgar R. Troxell, Jr., Bronxvlle, N. Y., assignor of one-half to Ralph P. Clarkson, New Rochelle, N. Y. Application August 18,

3 Claims.

My invention relates to distributing means, par--v ticularly for conditioned air, and has special reference to the provision of a non-overloading distributing head having `a high suction pressure and still maintaining free discharge of air' all around the periphery of an open fan.

It is generally recognized that a centrifugal fan of standard design has an extremely low efficiency, of the order of 10%, when maintaining free delivery of air without a discharge housing. It is further recognized that such a fan directly connected to a duct is subject to widevariation in motor speed and in motor load when the static pressure within the duct varies or is different from what the fan is designed to handle. Where high suction pressures are involved, it is particularly important to limit the loading of the fan caused by release of the suction pressure, as otherwise the consequent slowing up of the motor is apt to result4 in overheating and possible re.

An object of the present invention is to provide a simple, reliable, and inexpensive distributing head to` overcome these objections. A further object is to provide a distributing head that can be used in multiple on a common duct, the head being so devised that even if other heads are not operating and permit leakage of air back through them to the duct,` the operating heads will not be overloaded. Another object of this invention is to provide a distributing head so constructed that regardless of error in assuming the section head against which the ian will operate, the distributing head when installed is incapable of overload. A further object is to provide a fan particularly adapted for such a distributing head, capable of developing a high suction pressure eflciency when operating in the open with free discharge of air all around the periphery.

With 'the foregoing and other objects in View, aswill be apparent asthe description proceeds, my invention resides in the combination and arrangement of parts and in the details of construction described in this specification and particularly pointed out in the appended claims. I intend no limitations other than those of the claims, it being understood that changes may be made within the scope of what is claimed without departing from the spirit of the'nvention. In the drawing I have illustrated apreferred form which will accomplish the objects recited and embodies my invention. The drawing, however, is furnished solely for illustrative purposes and I do not desire to be understood as limiting myself to the specific structure therein shown.

In the drawing:

1934, ASerial No. 740,461

Fig. 1 is a conventional sectional elevation of a distributing head involving my invention and connected to a duct, usually with a number of other heads of identical construction;

` Fig. 2 is a plan view of a portion of the discharg-e ring showing the rubbing knobs;

Fig. 3 isa plan View showing a fragmentary detail of the arrangement of blades in the fan of Fig. 1; l

Fig. 4 is a plan View of the secondary chamber or throttling nozzle of Figs. l and 5;

Fig. 5 is an enlarged sectional elevational detail illustrativev of my invention;

Fig. 6 is an elevational View illustrative of a rubbing knob; 5

Fig. '7 is a conventional elevation illustrative of a portion of a duct with a plurality of distributing heads connected thereto;

Fig. 8 is a perspective sketch of the throttling nozzle of Figs 1 and 6;

Fig. 9 is a fragmentary perspective sketch of the assembly,omitting the rubbing knobs.

Similar reference characters refer to corresponding parts throughout the views.

Fig. 1 illustrates a diffusing and distributing head of the same general type as shown in copending application SerialNumber 711,643 filed Feb. 17, 1934, which application was abandoned Sept. 23, 1935 and is particularly designed to draw air from a duct 3 and discharge same into a space mixed with induced air from the space in the desired proportion drawn through openings I8.

The head comprises a suction housing 2, preferably a light weight casting, attached to the duct 3 and preferably supporting a motor I0 as by 35 straps 8, 8, fastened to the bosses I2, I2, and adjusting screws 9, 9, through support arms I l, I I. Preferably a felt collar (not shown) is placed around motor I0 to deaden vibration and to close whatever gap may exist between the motor and 40 the encircling portion of the housing 2. Attached to shaft I9 of motor I0 by a hub I is a fan disk 6 having a plurality of blades 5, 5, spaced at or near the outer edge of the disk.

A discharge ring III may beprovided, adjustably 45 supported by posts I5, I5, whereby the gap below fan disk 6 may be varied at will to provide varying amounts of induced air drawn through openings I in the closu e plate I1 which is removably attached to the c ver member I6, the latter, in 50 turn, being fastened to plate I4. In thiscon struction all moving parts are concealed from below but access to fan and motor is permitted.

Radially disposed on plate I4 I prefer to provide a plurality of rubbing knobs I3, I3, to create turbulence in the discharged air stream, thus dii'- fusing the discharged air into the space. These knobs, in rubbing the air stream also tend to shower the discharge downwardly and outwardly, the dash line A designating the normal position of ceiling or wall surface. Knobs Il are generally of semi-bulbous shape with the larger end towards the outside and, being symmetrical, the direction of rotation of the fan may be either way. Being set radially, the rubbing knobs Il lie across the discharge direction of the air, as indicated by the arrows (Fig. 2) and divert and diffuse it into the air of the space.

The particular fan which I prefer for this type of distributing head, in order to secure high suction pressure, has approximately the specific relationships shown in Fig. 3. A disk 6 has at or near its periphery a plurality of blades 5, 5, cornparatively narrow and close together. For a 12" diameter fan, 1750 R. P. M., delivering 450 cfm. against a suction pressure of 0.5" W. G. the preferred proportions of the various parts are approximately as shown in Figs. 3 and 5.

Essential features of such a fan are the angle at which the blades are set, and the backward angle or pitch of the blades with their concave faces forward as the fan rotates. In this instance the. rotation is counter-clockwise, as indicated by the arrow (Fig. 3). I prefer that the blades be formed in the arc of a circle of which a radius drawn from the center of the blade makes an angle of forty-five degrees with that radius of the blade circle which passes through the in- 'side leading edge of theblade. Similarly, the chord of the arc formed by the concave forward face of the blade is at 45 degrees to the same radius of the blade circle. Preferably, though not necessarily, a top ring l is provided to support the upper ends of the blades 5, 5. i. It will be observed that this fan is sealed on one face by the disk i and no air can enter the fan except from the throttling intake. Hence, only duct air is handled by the fan and the creation of a restricted suction intake by well known calculations for the flow of air through an orifice is not nuliified by leakage or flow of air to the blades from elsewhere.

Preferably suction housing 2 is formed by concentric tubular members spaced apart as by partitions I, I, the space between forming an air passage as indicated (Figs. 1 and 5) in the form of a throttling nozzle which may extend within the fan and deliver air to the inside oi.' the blades,

the entrance opening being of predetermined proportions based on the desired air deliwery and suction pressure to be developed. This forms, in substance, a secondary chamber between the duct and the fan with a restricted entrance so that if, for example, a number of such heads are attached to the same duct and 'one or more stop operating, thus temporarily permitting air to leak back through these non-operating heads to the duct, the operating heads will pt be overloaded. Similarly, if the coils for heating or cooling are removed from the duct circuit, the heads may still be operated for ventilation without overloading the motors by abnormal reduction in the speed of the fan because of loading. Nor will av leak in a ventilating duct circuit cause overloading of the distributing heads.

The reason for this prevention of overloading is that the construction described permits the air within duct I to reach the fan only by passage through the annular orifice and passageway created between the two concentric tubular members forming the suction housing. This throttling orifice is of a specific predetermined area for any given fan and thus limits the quantityof airwhich can flow from the duct to the fan when any given suction pressure is created by the fan within the suction housing.

Partitions I, I, also provide means to diminish the rotation or fanning" of the air drawn within the secondary chamber and aid in guiding the flow of air, without turbulence, to the blades.

It is apparent that the construction indicated in Fig. 5 may be used, if desired, without discharge ring I4, cover member I6, and closure plate I l, the fan running directly in the open air and having absolutely free discharge of air all around its periphery.` 'Ihe preferred construction, however, is that shown in Fig. 1 where substantially free discharge of air all around the periphery of the fan is obtained, the slight friction of air on plate Il and the diffusion caused by knobs I3 rubbing the discharged air being of little effect in theloading of the fan.

What I claim is:

, 1. In combination, a supply duct provided with a plurality of openings, a distributing head adjacent to eachv opening, each said head comprising an open centrifugal type suction fan having substantially free discharge of air all around its periphery, air intake means communicating with said duct on one face only of said fan, the other face of said fan being sealed whereby only duct air can pass through said fan when said fan is operating, a motor operatively connected to drive said fan, means included in the structure of each head providing an admixturey of air from the space served with the discharge of duct air from said fan, and means so constructed and arranged that change in the discharge of one of said distributing heads by reason of the stoppage of another of said heads and the leakage of space air back through said stopped head, is obviated.

2. In combination, an open centrifugal type suction fan having substantially free discharge of air all around its periphery, a housing for said fan on the suction face directing the flow of sucked in air to the interior edges of the blades of said fan, means to seal the other face of said fan from the intake of air, whereby only sucked in air passes through said fan blades when said fan is operating, a motor operatively connected to said fan and supported within said housing, and means providing an admixture of air from the spaced served with the discharge of sucked in air from said fan.

3. A structure as defined in claim 2 in which said last named means includes a discharge ring below said fan said ring being supported by said housing and provided with an opening for the passage of space air upwardly therethrough.

E. R. TROXELL, Jn. 

